Anaerobic digestion based waste-to-energy technologies can halve the climate impact of China’s fast-growing food waste by 2040

Abstract

Food waste (FW) has become a global sustainability challenge due partly to its significant environmental impacts (e.g., greenhouse gas (GHG) emissions) from traditional treatment methodologies such as landfill and incineration. This is particularly the case for developing countries, for example over 90% of FW in China is currently blended with municipal solid waste and disposed of by landfilling and incineration. The anaerobic digestion (AD) technologies for energy recovery, however, has often been identified as an effective approach for mitigating FW treatment related GHG emissions. In order to benchmark and quantify such reduction potentials, a dynamic model has been built to characterize the generation and flow of FW and treatment associated GHG emissions in China from 2001 to 2040. Our results show that the total FW generation from household and catering sectors reached 170 ± 30 Mt in 2018 and will steadily increase to approximately 220 ± 42 Mt by 2040. Accordingly, the FW treatment related GHG emissions reached 137 ± 26 Mt CO2e in 2018 and would rise to approximately 180 Mt±33 CO2e by 2040 if waste management continues with the current pattern in a Business As Usual (BAU) scenario. Compared to the BAU scenario, the scenarios subject to AD technology implementation (from conservative to optimistic) could significantly reduce GHG emissions and ensure a proportional contribution of this sector to China’s national emission reduction goal (55% by 2025 and 65% by 2030 compared to 2005). Specifically, a cumulative amount of approximately 1.9 Bt CO2e could be mitigated between 2019 and 2040 under the optimistic scenario (with 60%, 80%, and 80%, respectively, of household food waste, catering food waste, and waste cooking oil treated by AD). These findings could not only inform evidence-based policy making to facilitate the waste-to-energy development for FW treatment in China, but also shed light on the sustainable FW management and AD technology implementation in other developing countries.